Answer the question on the basis of the passage given below:
Oxides formed by \(p\)- block elements are acidic, basic and neutral. Also, elements of \(p\)-block form different acids.
Match List I with List II
| List I | List II |
| A. \(Pb_3O_4\) | I. Neutral |
| B. \(N_2O\) | II. Acidic |
| C. \(Mn_2O_7\) | III. Basic |
| D. \(Bi_2O_3\) | IV. Mixed |
Predict the nature of oxides.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A-IV, B-I, C-II, D-III
Oxides are classified by their reaction with water, acids and bases. An oxide that gives an acid with water is acidic (usually of non-metals and of metals in high oxidation states); one that gives a base is basic (metals in low oxidation states); one that reacts with both acids and alkalis is amphoteric; one with neither acidic nor basic properties is neutral. A mixed oxide contains the metal in two oxidation states.
(A) \( \ce{Pb3O4} \) — This matches (IV) Mixed. Red lead behaves as 2PbO·\( \ce{PbO2} \): lead in the +2 and +4 states.
(B) \( \ce{N2O} \) — This matches (I) neutral. \( \ce{N2O} \), like CO and NO, forms neither an acid nor a base.
(C) \( \ce{Mn2O7} \) — This matches (II) Acidic. Manganese is +7, its highest state; the oxide gives permanganic acid.
\( \ce{Mn2O7 + H2O -> 2HMnO4} \)
(D) \( \ce{Bi2O3} \) — This matches (III) Basic. Basic character of the group 15 oxides rises down the group; bismuth, the heaviest, gives a basic oxide.
\( \ce{Bi2O3 + 6HCl -> 2BiCl3 + 3H2O} \)
Shortcut: (A)-(IV) leaves Options (2) and (3); (B)-(I) leaves only Option (2).
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Simple Oxides – …
